Franklin Blake is in love with Rachel Verinder. The gem he gives her, the moonstone, disappears, and the police cannot solve the crime. Eventually, Rachel spurns Franklin, and he goes abroad in an attempt to forget her and recover. When Franklin's father dies and Franklin returns to England, he resolves to win her back by solving the mystery of the moonstone.
Mademoiselle Stangerson retires to bed in the Yellow Room. Suddenly revolver shots echo through the house and she screams for help. Her father and a servant run to the locked room where they find the wounded girl - alone. The only other exit, a window - barred. How had the assailant escaped?
Grace and Mercy are very different women, but are both caught up in the war between Germany and France. When Grace is hit by a loose shell, Mercy seizes the chance to escape her past as a fallen woman and convict by assuming Grace's identity and travelling to England.
This book follows a nameless, eccentric old man, sitting in the corner of a cozy London tea shop, using pure deduction to solve a series of baffling crimes--from gruesome murders and cases of deadly blackmail, to daring thefts and brilliant deceptions.